Scott Olson—Getty ImagesDemonstrators protest the killing of teenager Michael Brown outside Greater St. Marks Family Church, in St. Louis, while his family along with civil rights leader the Rev. Al Sharpton and others met inside to discuss the killing on Aug. 12, 2014

The Department of Justice is investigating whether there were any federal civil rights violations in the shooting death of an unarmed black teen in Missouri

A U.S. attorney announced Wednesday that his office is investigating whether Missouri police violated any federal civil rights laws during Saturday’s shooting death of Michael Brown, an unarmed black teenager. The investigation comes at the request of U.S. Attorney General Eric Holder.

U.S. Attorney for the Eastern District of Missouri Richard Callahan, acting Assistant Attorney General for the Civil Rights Division Molly Moran and FBI special agent in charge William Woods said in a joint statement they would also collaborate with local authorities while working to determine if there were any state-level violations.

Tensions have been running high in the St. Louis suburb of Ferguson since the shooting occurred. Residents have been holding sporadic protests since Saturday calling for, among other things, the name of the officer who shot Brown. Ferguson Police chief Thomas Jackson said at a press conference Wednesday his department would not be releasing the officer’s name because of concerns over death threats they’ve received.

The demonstrations, protests and street violence that’s followed the shooting have carried a strong undercurrent of racial undertones. Civil rights leaders have compared the shooting of Brown, an 18-year-old black man, to similar deaths of African-American youths by officers and vigilantes. On Wednesday, Jackson said his department was working with the Department of Justice to improve race and community relations.